llama-stack-mirror/llama_stack/distribution/access_control/access_control.py
Akram Ben Aissi b945525a9e chore: extract build_access_denied_message in its own function
Signed-off-by: Akram Ben Aissi <<akram.benaissi@gmail.com>>
2025-07-03 15:36:55 +02:00

131 lines
4.1 KiB
Python

# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the terms described in the LICENSE file in
# the root directory of this source tree.
from typing import Any
from llama_stack.distribution.datatypes import User
from .conditions import (
Condition,
ProtectedResource,
parse_conditions,
)
from .datatypes import (
AccessRule,
Action,
Scope,
)
def matches_resource(resource_scope: str, actual_resource: str) -> bool:
if resource_scope == actual_resource:
return True
return resource_scope.endswith("::*") and actual_resource.startswith(resource_scope[:-1])
def matches_scope(
scope: Scope,
action: Action,
resource: str,
user: str | None,
) -> bool:
if scope.resource and not matches_resource(scope.resource, resource):
return False
if scope.principal and scope.principal != user:
return False
return action in scope.actions
def as_list(obj: Any) -> list[Any]:
if isinstance(obj, list):
return obj
return [obj]
def matches_conditions(
conditions: list[Condition],
resource: ProtectedResource,
user: User,
) -> bool:
for condition in conditions:
# must match all conditions
if not condition.matches(resource, user):
return False
return True
def default_policy() -> list[AccessRule]:
# for backwards compatibility, if no rules are provided, assume
# full access subject to previous attribute matching rules
return [
AccessRule(
permit=Scope(actions=list(Action)),
when=["user in owners " + name for name in ["roles", "teams", "projects", "namespaces"]],
),
]
def is_action_allowed(
policy: list[AccessRule],
action: Action,
resource: ProtectedResource,
user: User | None,
) -> bool:
# If user is not set, assume authentication is not enabled
if not user:
return True
if not len(policy):
policy = default_policy()
qualified_resource_id = resource.type + "::" + resource.identifier
for rule in policy:
if rule.forbid and matches_scope(rule.forbid, action, qualified_resource_id, user.principal):
if rule.when:
if matches_conditions(parse_conditions(as_list(rule.when)), resource, user):
return False
elif rule.unless:
if not matches_conditions(parse_conditions(as_list(rule.unless)), resource, user):
return False
else:
return False
elif rule.permit and matches_scope(rule.permit, action, qualified_resource_id, user.principal):
if rule.when:
if matches_conditions(parse_conditions(as_list(rule.when)), resource, user):
return True
elif rule.unless:
if not matches_conditions(parse_conditions(as_list(rule.unless)), resource, user):
return True
else:
return True
# assume access is denied unless we find a rule that permits access
return False
def build_access_denied_message(action: str | None, resource: ProtectedResource | None, user: User | None) -> str:
"""Build detailed error message for access denied scenarios."""
if action and resource and user:
resource_info = f"{resource.type}::{resource.identifier}"
user_info = f"'{user.principal}'"
if user.attributes:
attrs = ", ".join([f"{k}={v}" for k, v in user.attributes.items()])
user_info += f" (attributes: {attrs})"
message = f"User {user_info} cannot perform action '{action}' on resource '{resource_info}'"
else:
message = "Insufficient permissions"
return message
class AccessDeniedError(RuntimeError):
def __init__(self, action: str | None = None, resource: ProtectedResource | None = None, user: User | None = None):
self.action = action
self.resource = resource
self.user = user
message = build_access_denied_message(action, resource, user)
super().__init__(message)